'large--one-quarter large-up--one-quarter medium--one-third medium-up--one-third small--one-half large--col-3 medium--col-4 small--col-6' %}

You do not have a link list with a handle set to brands-we-love, or you do and it's empty. Go ahead and create a link list called Brands We Love on your Navigation page and populate that link list with links that point to collections, to see collections listed here. Make sure the link list also has a handle set to brands-we-love.